Quantcast

Cadmium-free amber automotive lamp

Imported: 23 Feb '17 | Published: 22 Oct '02

Johnny D. Bryant, William F. Buchman, Jr.

USPTO - Utility Patents

Abstract

An automotive lamp including a sealed envelope having a filament or other light emitting element contained therein, with the envelope being formed from a barium-silicate based glass that is essentially free of cadmium and that includes barium oxide in the range of 2.15%-2.25% by weight, strontium oxide in the range of 5.58%-5.82% by weight, potassium oxide in the range of 8.9%-9.3% by weight, and molybdenum oxide in the range of 0.068%-0.072% by weight. Specific amounts of other constituent components of the glass are also disclosed. The resulting lamp provides an amber color that meets applicable CIE chromaticity requirements for automotive lamps and the glass exhibits physical characteristics that are closely matched to that of lime glass, making it suitable for standard lamp manufacturing processes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred exemplary embodiment of the invention will hereinafter be discussed in conjunction with the appended drawings, wherein like designations denote like elements, and wherein:

FIG. 1 is a front view of an automotive lamp constructed in accordance with the invention;

FIG. 2 is a side view of the automotive lamp of FIG. 1;

FIG. 3 is a cross-sectional view of the wedge base portion of the lamp of FIG. 1 taken along with the

3

3 line of FIG. 1; and

FIG. 4 is a graph depicting the CIE chromaticity boundaries for amber color lamps used in the United States.

Claims

1. An automotive lamp for use in exterior vehicle lighting applications, said lamp including a sealed envelope having a light emitting element contained therein, wherein said envelope is formed from a barium-silicate based glass that is essentially free of cadmium and that comprises barium oxide in the range of 2.15%-2.25% by weight and strontium oxide in the range of 5.58%-5.82% by weight.

2. An automotive lamp as defined in claim 1, wherein said glass further comprises potassium oxide in the range of 8.9%-9.3% by weight and molybdenum oxide in the range of 0.068%-0.072% by weight.

3. An automotive lamp as defined in claim 1, wherein said light emitting element comprises a tungsten filament mounted within said envelope.

4. An automotive lamp as defined in claim 3, further comprising a second tungsten filament mounted within said envelope, wherein said filaments are spaced from each other within said envelope.

5. An automotive lamp as defined in claim 3, wherein said lamp includes a wedge base comprising a sealed lower portion of said envelope.

6. An automotive lamp as defined in claim 5, wherein said lamp includes a pair of lead-in wires that support said filament within said envelope and that extend through said wedge base from an exposed location on an outside surface of said envelope to an interior region of said envelope.

7. An automotive lamp as defined in claim 5, wherein said wedge base further comprises a plastic sleeve attached to said sealed lower portion of said envelope.

8. An automotive lamp for use in exterior vehicle lighting applications, said lamp including a sealed envelope of amber color having a light emitting element contained therein, wherein said envelope is formed from glass that is essentially free of cadmium and that consists essentially of the following elements in amounts that are within 2% the following weight percentages:

9. An automotive lamp as defined in claim 8, wherein said light emitting element comprises a tungsten filament mounted within said envelope.

10. An automotive lamp as defined in claim 9, further comprising a second tungsten filament mounted within said envelope, wherein said filaments are spaced from cach other within said envelope.

11. An automotive lamp as defined in claim 9, wherein said lamp includes a wedge base comprising a sealed lower portion of said envelope.

12. An automotive lamp as defined in claim 11, wherein said lamp includes a pair of lead-in wires that support said filament within said envelope and that extend through said wedge base from an exposed location on an outside surface of said envelope to an interior region of said envelope.

13. An automotive lamp as defined in claim 11, wherein said wedge base further comprises a plastic sleeve attached to said sealed lower portion of said envelope.

14. A method of manufacturing an automotive lamp, comprising the steps of:

15. The method of claim 14, wherein step (c) further comprises inserting a tungsten filament assembly into said glass tube, where said tungsten filament assembly includes a tungsten filament mounted on a pair of lead-in wires with an insulating bridge that physically maintains separate of the lead-in wires to thereby maintain electrical isolation of the lead-in wires from each other.

16. The method of claim 15, wherein step (d) further comprises melting the glass together into a wedge base such that the lead-in wires extend from the bridge through the wedge base and out to an exposed location outside of said envelope.

17. The method of claim 16, wherein step (d) further comprises bending the lead-in wires at the exposed location so that they rest upon the outside surface of the envelope.

18. The method of claim 16, further comprising the step of (e) attaching a plastic sleeve to the wedge base.

19. The method of claim 15, wherein said tungsten filament assembly includes a second tungsten filament mounted on a second pair of lead-in wires that are supported by said bridge in electrical isolation from each other.

20. The method of claim 14, wherein step (c) further comprises inserting a getter into the glass tube and wherein step (d) further comprises replacing air in the glass tube with an inert gas during sealing of said other end.